product-vamp/generator/comping.py

"""Source-only accompaniment: joint layered rhythms and connected grips."""
from __future__ import annotations
import copy
import dataclasses
import fractions
import functools
import json
import typing

import generator.accompaniment
import generator.acoustic
import generator.acoustic_voicing
import generator.arrange.form
import generator.chord_families
import generator.comping_rhythm
import generator.fretboard
import generator.guitar
import generator.harmony
import generator.hand_position
import generator.model
import generator.parts
import generator.score
import generator.solo.policy
import generator.vocabulary

def semantic_key(chord):
  return json.dumps({k: chord[k] for k in ('root', 'kind', 'degrees', 'bass', 'inversion') if k in chord}, sort_keys=True)

def requirements(chord, part):
  result = generator.fretboard.chord_requirements(chord, respect_bass=part != 'electric')
  if part == 'electric' or result.basses:
    return result
  degrees = generator.harmony.degrees(chord)
  plain = degrees in ({1: 0, 3: 0, 5: 0}, {1: 0, 3: -1, 5: 0})
  root = int(generator.model.NATURAL[chord['root']['letter']] + generator.model.alteration(chord['root']['alter']))
  basses = tuple(sorted({(root + generator.harmony.degree_semitones(d, degrees[d])) % 12 for d in ((1, 3, 5) if plain else (1, 5)) if d in degrees}))
  if not basses:
    raise ValueError('acoustic accompaniment requires a written bass, root or fifth')
  return dataclasses.replace(result, basses=basses)

def voicings(key, part, *, composition=None):
  return _voicings(key, part, composition or generator.vocabulary.current())

@functools.lru_cache(maxsize=2048)
def _voicings(key, part, composition):
  chord = json.loads(key)
  required = requirements(chord, part)
  if part == 'electric':
    options = generator.guitar.chord_positions(required, prune=False, profile='electric', composition=composition)
  elif part == 'acoustic':
    degrees = generator.harmony.degrees(chord)
    plain = degrees in ({1: 0, 3: 0, 5: 0}, {1: 0, 3: -1, 5: 0})
    options = tuple(v for v in generator.acoustic_voicing.candidates(required, plain)
      if v.bass.fret <= generator.fretboard.MAX_SINGLE_FRET
      and generator.fretboard.has_fret_anchor(v[1:])
      and (not plain or set(required.allowed) <= {p.midi % 12 for p in v}))
  else:
    raise ValueError('Unknown accompaniment instrument: ' + part)
  options = tuple(v for v in options if generator.fretboard.playable_attack((p, fractions.Fraction(1)) for p in v))
  if not options:
    layout = 'bass on 5/6 plus upper strings 2/3/4' if part == 'acoustic' else 'melody chord families on strings 1–4'
    raise ValueError(f'{generator.harmony.symbol(chord)}: no legal {part} voicing ({layout}); required degrees/bass, no open strings, fret anchor 1–12 and at most {generator.fretboard.MAX_FRET_SPAN} consecutive frets remain binding')
  return tuple(sorted(options))

def movement(part, previous, current, old_hand, hand):
  return generator.hand_position.motion(previous, current, old_hand, hand, part == 'acoustic').shift

class VoicingCost(typing.NamedTuple):
  extended_grips: int = 0
  family: int = 0
  travel: int = 0
  peak_position: int = 0
  effort: fractions.Fraction = fractions.Fraction()
  missing_tones: int = 0
  register: fractions.Fraction = fractions.Fraction()
  def plus(self, other):
    return VoicingCost(*(max(a, b) if field == 'peak_position' else a + b for field, a, b in zip(self._fields, self, other)))
  def moved(self, distance, ergonomics=0):
    return self._replace(travel=self.travel + distance, effort=self.effort + ergonomics)

def local_cost(part, key, grip, center, *, composition=None):
  composition = composition or generator.vocabulary.current()
  required = requirements(json.loads(key), part)
  register = generator.guitar.voicing_preferences(grip, generator.guitar.voicing_preference(part + '_accompaniment', center, composition=composition))
  if part == 'electric':
    value = generator.guitar.voicing_cost(grip, 'electric', required.allowed, composition=composition)
    return VoicingCost(extended_grips=value.extended_grips, family=3 * value.string_shortfall + value.family_penalty, effort=value.effort, missing_tones=value.missing_tones, register=register)
  # Keep the familiar families, then compare physical effort before position.
  # Sounding register only breaks otherwise equal placement decisions.
  family = generator.chord_families.acoustic(json.loads(key), grip, composition=composition)
  return VoicingCost(extended_grips=generator.fretboard.span_penalty(grip), family=int(not family['preferred']), missing_tones=len(set(required.allowed) - {p.midi % 12 for p in grip}), register=register)

def select_grips(layers, costs, part, seed, *, left=(), right=(), left_hand=None, right_hand=None, close=False, fixed_hands=None):
  """Return complete grips, cost and hand windows, including repeat travel.

  A concrete grip may occupy several windows. Preserve distinct earlier peaks
  at a common grip/hand, and fix both starting values for a cyclic path.
  """
  if not layers:
    return (), VoicingCost(), ()

  def hands(grip, fixed=None):
    options = generator.hand_position.regions(grip)
    if fixed is not None:
      return tuple(h for h in options if h == fixed)
    return options

  retained = []
  for i, layer in enumerate(layers):
    tier = min(costs[i][v].extended_grips for v in layer)
    fixed = fixed_hands[i] if fixed_hands is not None else None
    options = tuple((v, h) for v in layer if costs[i][v].extended_grips == tier for h in hands(v, fixed))
    if not options:
      raise ValueError(f'accompaniment span {i}: no grip fits the committed hand position')
    retained.append(options)
  ranks = [{v: generator.solo.policy.stable_rank(seed, (i, v)) for v, _ in layer} for i, layer in enumerate(retained)]
  winners = []
  for first in retained[0] if close else [None]:
    states = {(left, h, h): (VoicingCost(peak_position=h), (), (), ()) for h in hands(left, left_hand)}
    for i, layer in enumerate(retained):
      following = {}
      for grip, hand in [first] if i == 0 and first is not None else layer:
        local = costs[i][grip]._replace(peak_position=hand)
        for (previous, old_hand, _), (cost, ties, path, positions) in states.items():
          motion = generator.hand_position.motion(previous, grip, old_hand, hand, part == 'acoustic')
          total = cost.plus(local).moved(motion.shift, motion.ergonomics)
          candidate = (total, (*ties, (ranks[i][grip], hand)), (*path, grip), (*positions, hand))
          key = (grip, hand, total.peak_position)
          if key not in following or candidate < following[key]:
            following[key] = candidate
      # Future travel is identical at a common concrete grip and hand.
      best = {}
      for (grip, hand, _), value in following.items():
        primary = value[0][:3]
        best[grip, hand] = min(best.get((grip, hand), primary), primary)
      states = {key: value for key, value in following.items() if value[0][:3] == best[key[:2]]}
    endpoints = [first] if close else [(right, h) for h in hands(right, right_hand)]
    for (grip, hand, _), (cost, ties, path, positions) in states.items():
      for endpoint, end_hand in endpoints:
        motion = generator.hand_position.motion(grip, endpoint, hand, end_hand, part == 'acoustic')
        total = cost.plus(VoicingCost(peak_position=end_hand)).moved(motion.shift, motion.ergonomics)
        winners.append((total, ties, path, positions))
  if not winners:
    raise ValueError('accompaniment boundary grip does not fit the committed hand position')
  cost, _, path, positions = min(winners)
  return path, cost, positions

@dataclasses.dataclass(frozen=True)
class HarmonyChoice:
  index: int
  start: fractions.Fraction
  end: fractions.Fraction
  chord: dict
  events: tuple
  figure: dict
  options: tuple
  hand: int | None = None
  @property
  def key(self):
    return (self.index, self.start, self.end, semantic_key(self.chord), self.events)

def split_measures(flat, inputs, part):
  """Project a selected sounding figure into notation; barlines create ties only."""
  output, fragments, original = [], {}, {}
  cursor = fractions.Fraction()
  for m, prior, index in inputs:
    length = generator.model.fraction(m['duration'])
    result = generator.parts.build_measure(m, f'comp_{part}_{index}', 'rest', part, prior)
    voices = []
    for voice in flat['voices']:
      notes = []
      for n in voice['notes']:
        start = generator.model.fraction(n['onset'])
        end = start + generator.model.fraction(n['duration'])
        a, b = max(cursor, start), min(cursor + length, end)
        if a >= b:
          continue
        for duration, written in generator.accompaniment.written_durations(b - a):
          pitches = [{k: v for k, v in p.items() if k not in ('tie_from', 'tie_to')} for p in n['pitches']]
          event = generator.model.make_event(f'comp_{part}_{index}_{voice["id"]}_{len(notes)}', a - cursor, duration, 'note' if pitches else 'rest', pitches, written)
          event['voice'] = voice['id']
          for old, new in zip(n['pitches'], event['pitches']):
            fragments.setdefault(old['id'], []).append(new)
            original[old['id']] = old
          notes.append(event)
          a += duration
      voices.append({'id': voice['id'], 'notes': notes})
    result['voices'] = voices
    for chord in result['harmonies']:
      chord.pop('chord_optional', None)
    output.append(result)
    cursor += length
  for pieces in fragments.values():
    for a, b in zip(pieces, pieces[1:]):
      a['tie_to'], b['tie_from'] = b['id'], a['id']
  for identifier, old in original.items():
    if old.get('tie_to') in fragments:
      a, b = fragments[identifier][-1], fragments[old['tie_to']][0]
      a['tie_to'], b['tie_from'] = b['id'], a['id']
  return tuple(output)

class Canonical:
  def __init__(self, document, part, seed, *, composition=None, plan=None):
    self.composition = composition or generator.vocabulary.current()
    self.part, self.seed = part, seed
    self.policy = self.composition.role(part + '_accompaniment')
    self.cache, self._reports, self._rhythm_reports = {}, {}, {}
    self.cache_positions = {}
    self.last_position = ((), 0)
    self.measures = generator.score.source_staff(document)['measures']
    # A held accompaniment chord may continue into the bar containing the
    # source melody pickup. Keep its voice identity through that splice.
    self.voice_id = self.measures[0]['voices'][0]['id']
    self.melody = generator.comping_rhythm.melody_contexts(document)
    self.first = generator.score.body_start_measure_index(self.measures)
    plan = plan or generator.arrange.form.FormPlan.read(document, part)
    sections = plan.sections
    self.closed = any(a.role == b.role == 'accompaniment' and a.source_measure_index + a.measure_count == len(self.measures)
      and b.source_measure_index == self.first for a, b in zip(sections, sections[1:]))
    carried = generator.accompaniment.carried_chords(self.measures)
    self.groups = []
    index = self.first
    while index < len(self.measures):
      size = 1
      if index + 1 < len(self.measures):
        lengths = [generator.model.fraction(m['duration']) for m in self.measures[index:index + 2]]
        if self.measures[index]['time_signature'] == self.measures[index + 1]['time_signature'] and any(tuple(map(fractions.Fraction, p['lengths'])) == tuple(lengths) for p in self.composition.accompaniment(part)['patterns']):
          size = 2
      self.groups.append(tuple((self.measures[i], carried[i], i) for i in range(index, index + size)))
      index += size
    self.acoustic_cache = {}
    self.pair_breaks = {self.first, len(self.measures)}
    self.pair_stops = []
    for section in sections:
      if section.role == 'accompaniment':
        self.pair_breaks.update((section.source_measure_index, section.source_measure_index + section.measure_count))
    self.pair_stops = [stop for section, stop in zip(sections, plan.stops) if section.role == 'accompaniment' and stop is not None]
    breaks = [(i, fractions.Fraction()) for i in self.pair_breaks] + self.pair_stops
    choices, locations, self.groove_report = generator.comping_rhythm.choose_cycles(self.groups, part, self.melody, seed, breaks=breaks, composition=self.composition)
    self.patterns = {g[0][2]: (p, a) for g, (p, a, _) in zip(self.groups, choices)}
    self.locations = {g[0][2]: location for g, location in zip(self.groups, locations)}
    selected = [r for _, _, r in choices]
    self.block_rhythms = {group[0][2]: rhythm for group, rhythm in zip(self.groups, selected)}
    prepared = [self.prepare(group, rhythm) for group, rhythm in zip(self.groups, selected)]
    active = tuple(span for spans in prepared for span in spans if span.events)
    self.canonical_spans = {group[0][2]: spans for group, spans in zip(self.groups, prepared)}
    path, self.path_cost, self.hand_order = self.select(active, close=self.closed)
    self.base = dict(zip((s.key for s in active), path))
    self.hands = dict(zip((s.key for s in active), self.hand_order))
    self.order = tuple((s.index, s.start, v) for s, v in zip(active, path))
    self.rhythms = {}
    previous = (path[-1], self.hand_order[-1]) if self.closed and path else ((), 0)
    for group, rhythm, spans in zip(self.groups, selected, prepared):
      grips = tuple((self.base[s.key], self.hands[s.key]) for s in spans if s.events)
      key = (self.key(group), rhythm.signature) if part == 'acoustic' else self.key(group)
      self.cache[key], self.cache_positions[key] = self.render(group, rhythm, spans, grips, previous, False)
      cursor = fractions.Fraction()
      for m, _, i in group:
        length = generator.model.fraction(m['duration'])
        self.rhythms[i] = dataclasses.replace(rhythm, events=tuple(dataclasses.replace(e, start=max(e.start, cursor) - cursor, end=min(e.end, cursor + length) - cursor, harmonic_time=e.harmonic_time - cursor if e.harmonic_time is not None else None) for e in rhythm.events if e.start < cursor + length and e.end > cursor))
        cursor += length
      if grips:
        previous = grips[-1]
  @property
  def report(self):
    return [row for key in sorted(self._reports, key=repr) for row in self._reports[key]]
  @property
  def placement_report(self):
    previous = self.hand_order[-1] if self.closed and self.hand_order else None
    shifts = []
    for hand in self.hand_order:
      shifts.append(abs(hand - previous) if previous is not None else 0)
      previous = hand
    return {'version': generator.hand_position.VERSION, 'priority': 'hand travel, maximum hand position, ergonomics, coverage/register, stable tie',
      **generator.hand_position.summary(shifts), 'peak_position': self.path_cost.peak_position,
      'cost': {k: str(v) for k, v in self.path_cost._asdict().items()},
      'positions': [{'source_index': i, 'onset': str(t), 'hand_position': h} for (i, t, _), h in zip(self.order, self.hand_order)]}
  @property
  def rhythm_report(self):
    return [row for key in sorted(self._rhythm_reports, key=repr) for row in self._rhythm_reports[key]]
  @staticmethod
  def key(inputs, limit=None):
    return (tuple((i, str(generator.model.fraction(m['duration'])), tuple((str(a), str(b), semantic_key(c) if c else '') for a, b, c in generator.comping_rhythm.spans(m, p))) for m, p, i in inputs), str(limit))
  def candidates(self, inputs, limit=None):
    flat = generator.comping_rhythm.flatten(inputs)
    melody, cursor, lengths = [], fractions.Fraction(), []
    for m, _, i in inputs:
      melody.extend((a + cursor, b + cursor) for a, b in self.melody[i])
      lengths.append(generator.model.fraction(m['duration']))
      cursor += lengths[-1]
    return generator.comping_rhythm.candidates(flat, None, self.part, tuple(melody), self.seed + '/' + str(inputs[0][2]), lengths=tuple(lengths), limit=limit, composition=self.composition)
  def acoustic_realizations(self, sources, bounds=None, stop=None):
    """Assign the canonical attack stream once, before splitting it into blocks.

    A variant uses the same patterns with the source's actual harmony and
    participation boundaries. No selected notes from another role enter here.
    """
    carried = generator.accompaniment.carried_chords(sources)
    full = tuple((m, carried[i], i) for i, m in enumerate(sources))
    key = (self.key(full), bounds, stop)
    if key in self.acoustic_cache:
      return self.acoustic_cache[key]
    starts = [fractions.Fraction()]
    for m in sources:
      starts.append(starts[-1] + generator.model.fraction(m['duration']))
    breaks = [(i, fractions.Fraction()) for i in self.pair_breaks | set(bounds or ())] + self.pair_stops
    if stop:
      breaks.append(stop)
    groups, raw = [], []
    for original in self.groups:
      group = tuple(full[i] for _, _, i in original)
      index = group[0][2]
      pattern, anticipate = self.patterns[index]
      limit = starts[stop[0]] + stop[1] - starts[index] if stop and any(i == stop[0] for _, _, i in group) else None
      rhythm = generator.comping_rhythm.realize(pattern, group, 'acoustic', self.melody, anticipate=anticipate, limit=limit, boundary=True, assign=False)
      if rhythm is None:
        raise ValueError(f'source measure {sources[index]["number"]}: selected acoustic rhythm cannot fit written harmony')
      raw.append(rhythm)
      groups.append(group)
    context = generator.comping_rhythm.acoustic_context(groups, self.melody, breaks)
    realized = generator.comping_rhythm.realize_acoustic_form(raw, context)
    result = {g[0][2]: r for g, r in zip(groups, realized)}
    self.acoustic_cache[key] = result
    return result
  def prepare(self, inputs, rhythm):
    flat = generator.comping_rhythm.flatten(inputs)
    spans = []
    offsets, cursor = [], fractions.Fraction()
    for m, _, i in inputs:
      offsets.append((cursor, i))
      cursor += generator.model.fraction(m['duration'])
    for start, end, chord in generator.comping_rhythm.spans(flat, None):
      if not chord:
        continue
      offset, index = next((a, i) for a, i in reversed(offsets) if a <= start)
      events = tuple(e for e in rhythm.events if start <= (e.harmonic_time if e.harmonic_time is not None else e.start) < end)
      try:
        options = voicings(semantic_key(chord), self.part, composition=self.composition)
      except ValueError as error:
        raise ValueError(f'source measure {inputs[index - inputs[0][2]][0]["number"]}, beat {start - offset + 1}: {error}') from error
      spans.append(HarmonyChoice(index, start, end, chord, events, dict(rhythm.families), options))
    return tuple(spans)
  def select(self, spans, *, left=(), right=(), left_hand=None, right_hand=None, close=False):
    layers = tuple(s.options for s in spans)
    costs = tuple({v: local_cost(self.part, semantic_key(s.chord), v, self.policy.get('center', 55), composition=self.composition) for v in layer} for s, layer in zip(spans, layers))
    return select_grips(layers, costs, self.part, self.seed, left=left, right=right, left_hand=left_hand, right_hand=right_hand, close=close, fixed_hands=tuple(s.hand for s in spans))
  def __call__(self, source, prior, index, *, sources=None, bounds=None, stop=None):
    group = next((g for g in self.groups if any(i == index for _, _, i in g)), ((source, prior, index),))
    original_group = group
    sources = sources or self.measures
    if self.part == 'acoustic' and source != sources[index]:
      sources = [source if i == index else m for i, m in enumerate(sources)]
    carried = generator.accompaniment.carried_chords(sources)
    low, high = bounds or (self.first, len(sources))
    group = tuple((source if i == index else sources[i], prior if i == index else carried[i], i) for _, _, i in group if low <= i < high)
    limit = None
    if stop and any(i == stop[0] for _, _, i in group):
      limit = sum((generator.model.fraction(m['duration']) for m, _, i in group if i < stop[0]), fractions.Fraction()) + stop[1]
    key = self.key(group, limit)
    complete = None
    if self.part == 'acoustic' and original_group[0][2] in self.patterns:
      complete = self.acoustic_realizations(sources, (low, high), stop)[original_group[0][2]]
      key = (key, complete.signature)
    if key not in self.cache:
      start, end = group[0][2], group[-1][2]
      offset = sum((generator.model.fraction(m['duration']) for m, _, i in original_group if i < start), fractions.Fraction())
      if original_group[0][2] in self.patterns:
        pattern, anticipate = self.patterns[original_group[0][2]]
        if self.part == 'acoustic':
          end_time = offset + (limit if limit is not None else sum(generator.model.fraction(m['duration']) for m, _, _ in group))
          rhythm = dataclasses.replace(complete, events=tuple(dataclasses.replace(e, start=max(e.start, offset) - offset, end=min(e.end, end_time) - offset, harmonic_time=e.harmonic_time - offset if e.harmonic_time is not None and e.harmonic_time >= offset else None)
            for e in complete.events if e.start < end_time and e.end > offset))
        elif offset:
          # Fit the incoming context before slicing. A raw template sustain
          # may already have ended at a chord change; projecting it first
          # would resurrect that note as an unintended new downbeat attack.
          context = tuple((source if i == index else sources[i], prior if i == index else carried[i], i)
            for _, _, i in original_group if i <= end)
          incoming = generator.comping_rhythm.realize(pattern, context, self.part, self.melody, anticipate=anticipate, limit=offset + limit if limit is not None else None, boundary=True)
          if incoming is None:
            raise ValueError(f'source measure {source["number"]}: selected groove cannot fit incoming harmony')
          pattern = {**pattern, 'events': [{'onset': str(e.start), 'duration': str(e.end - e.start),
            'layer': e.lane, 'anticipate': e.harmonic_time is not None and e.lane in ('upper', 'electric')} for e in incoming.events]}
        if self.part != 'acoustic':
          pattern = generator.comping_rhythm.project(pattern, offset, tuple(generator.model.fraction(m['duration']) for m, _, _ in group))
          rhythm = generator.comping_rhythm.realize(pattern, group, self.part, self.melody, anticipate=anticipate, limit=limit, boundary=True)
        if rhythm is None:
          raise ValueError(f'source measure {source["number"]}: selected groove cannot fit protected boundary')
      else:
        # A source pickup outside the repeating body uses the existing partial
        # vocabulary. It never selects or changes the body groove.
        rhythm = min(self.candidates(group, limit), key=lambda r: (r.cost, generator.solo.policy.stable_rank(self.seed, r.signature)))
      spans = self.prepare(group, rhythm)
      # Keep every unchanged harmonic interval's canonical grip, even when a
      # neighbor loses an optional turnaround or a section starts mid-pattern.
      fixed = []
      for span in spans:
        original = next((s for s in self.canonical_spans.get(original_group[0][2], ()) if s.key in self.base
          and s.start <= span.start + offset < s.end and semantic_key(s.chord) == semantic_key(span.chord)), None)
        fixed.append(dataclasses.replace(span, options=(self.base[original.key],), hand=self.hands[original.key]) if original else span)
      spans = tuple(fixed)
      before = [(v, h) for (i, _, v), h in zip(self.order, self.hand_order) if i < start]
      after = [(v, h) for (i, _, v), h in zip(self.order, self.hand_order) if i > end]
      left = before[-1] if before else (self.order[-1][2], self.hand_order[-1]) if self.closed and self.order else ((), 0)
      right = after[0] if after else (self.order[0][2], self.hand_order[0]) if self.closed and self.order else ((), 0)
      selected, _, hands = self.select(tuple(s for s in spans if s.events), left=left[0], right=right[0], left_hand=left[1], right_hand=right[1])
      self.cache[key], self.cache_positions[key] = self.render(group, rhythm, spans, tuple(zip(selected, hands)), left, True, limit)
    placement = self.cache_positions[key][index - group[0][2]]
    if placement is not None:
      self.last_position = placement
    return copy.deepcopy(self.cache[key][index - group[0][2]])
  def render(self, inputs, rhythm, spans, selected, previous, variant, limit=None):
    flat = generator.comping_rhythm.flatten(inputs)
    length = generator.model.fraction(flat['duration'])
    index = inputs[0][2]
    attacks, rows, placed_events = [], [], []
    choices = iter(selected)
    for span in spans:
      grip, hand = next(choices) if span.events else ((), 0)
      motion = generator.hand_position.motion(previous[0], grip, previous[1], hand, self.part == 'acoustic')
      bass = grip[0] if grip and self.part == 'acoustic' else None
      degrees = generator.harmony.degrees(span.chord)
      root = int(generator.model.NATURAL[span.chord['root']['letter']] + generator.model.alteration(span.chord['root']['alter']))
      rows.append({'source_index': span.index, 'onset': str(span.start), 'chord': generator.harmony.symbol(span.chord),
        'figure': span.figure, 'pattern_id': rhythm.pattern_id, 'tones': len(grip), 'bass': bool(bass), 'variant': variant,
        'family': (generator.chord_families.acoustic(span.chord, grip, composition=self.composition) if self.part == 'acoustic' else generator.chord_families.electric(grip)) if grip else None,
        'family_coverage': generator.chord_families.coverage(span.chord, span.options, self.part, composition=self.composition),
        'fret_span': generator.fretboard.fret_span(grip),
        'span_group': ('fallback' if generator.fretboard.span_penalty(grip) else 'primary') if grip else None,
        'span_candidates': generator.chord_families.span_coverage(span.options),
        'positions': [{'string': p.string_number, 'fret': p.fret, 'sounding_midi': p.midi} for p in grip],
        'bass_degree': next((d for d, a in degrees.items() if bass and (root + generator.harmony.degree_semitones(d, a)) % 12 == bass.midi % 12), None),
        'bass_string': bass.string_number if bass else None,
        'movement': motion.shift, 'voicing_candidates': len(span.options)})
      if grip:
        local = local_cost(self.part, semantic_key(span.chord), grip, self.policy.get('center', 55), composition=self.composition)
        rows[-1]['hand_position'] = hand
        rows[-1]['voicing_cost'] = {'movement': motion.shift, 'hand_shift': motion.shift, 'finger_adjustment': motion.fingers,
          'string_changes': motion.strings, 'grip_effort': str(local.effort), 'register_tiebreak': str(local.register),
          'secondary_effort': str(motion.ergonomics + local.effort)}
      for event in span.events:
        placed_events.append((event.start, event.end, (grip, hand)))
        lanes = ['bass', 'upper'] if event.lane == 'combined' else [event.lane]
        for lane in lanes:
          positions = (grip[0],) if lane == 'bass' else grip[1:] if lane == 'upper' else grip
          attacks.append((lane, event.start, event.end, positions, span.chord))
      if grip:
        previous = (grip, hand)
    key = self.key(inputs, limit)
    if self.part == 'acoustic':
      key = (key, rhythm.signature)
    measure_hands, cursor = [], fractions.Fraction()
    for m, _, _ in inputs:
      end = cursor + generator.model.fraction(m['duration'])
      played = sorted((a, b, p) for a, b, p in placed_events if a < end and b > cursor)
      measure_hands.append(played[-1][2] if played else None)
      cursor = end
    self._reports[key] = rows
    voices = []
    for lane in ['upper', 'bass'] if self.part == 'acoustic' else ['electric']:
      voice_id = lane if self.part == 'acoustic' else self.voice_id
      notes, cursor = [], fractions.Fraction()
      def emit(a, b, positions=(), chord=None):
        previous = None
        for duration, written in generator.accompaniment.written_durations(b - a):
          pitches = generator.fretboard.chord_pitches(chord, positions) if positions else []
          n = generator.model.make_event(f'comp_{self.part}_{index}_{lane}_{len(notes)}', a, duration, 'note' if pitches else 'rest', pitches, written)
          n['voice'] = voice_id
          if previous and pitches:
            for old, new in zip(previous['pitches'], n['pitches']):
              old['tie_to'], new['tie_from'] = new['id'], old['id']
          notes.append(n)
          previous = n
          a += duration
      for _, start, end, positions, chord in sorted((e for e in attacks if e[0] == lane), key=lambda e: e[1]):
        if cursor < start:
          emit(cursor, start)
        emit(start, end, positions, chord)
        cursor = end
      if cursor < length:
        emit(cursor, length)
      voices.append({'id': voice_id, 'notes': notes})
    result = split_measures({'voices': voices}, inputs, self.part)
    if self.part == 'acoustic':
      generator.acoustic.validate_assignment(result, rhythm.events)
    reports, cursor = [], fractions.Fraction()
    for m, _, i in inputs:
      duration = generator.model.fraction(m['duration'])
      reports.append({'source_index': i, 'pattern_id': rhythm.pattern_id, 'pattern_start': index,
        **next((self.locations[g[0][2]] for g in self.groups if any(j == i for _, _, j in g)), {}),
        'families': dict(rhythm.families), 'contributions': dict(rhythm.contributions), 'selection_cost': rhythm.cost,
        'exceptions': rhythm.exceptions, 'source_melody': [(str(a), str(b)) for a, b in self.melody[i]],
        'events': [{'layer': e.lane, 'onset': str(max(e.start, cursor) - cursor), 'duration': str(min(e.end, cursor + duration) - max(e.start, cursor)),
          'continuation': e.start < cursor, 'harmonic_target': str(e.harmonic_time - cursor) if e.harmonic_time is not None else None} for e in rhythm.events if e.start < cursor + duration and e.end > cursor]})
      cursor += duration
    self._rhythm_reports[key] = reports
    return result, tuple(measure_hands)